Thread-measuring mechanism for boot and shoe sewing machines.



No. 818,360. PATENTED APR.1'7, 1906.

M, T. DBNNE.' THREAD MEASURING MECHANISM FOR BOOT AND SHOE SEWING MACHINES.

APPLIOATION FILED MAY 9, 1904.

' 2 SHEETS-SHEET 1.

Jul/ado]? JAM M SM No. 818,360. PATENTED APR. 17, 1906.

' M. T. DENNB.

THREAD MEASURING MECHANISM FOR BOOT AND SHOE SEWING MACHINES APPLICATION FILED MAYQ. 1904-.

2 SHEETSSHEET 2,

UNITED STATES PATENT OFFICE.

MARK THOMAS DENNE, OF RUSHDEN, ENGLAND.

THREAD-MEASURING MECHANISM FOR BOOT AND SHOE SEWING MACHINES.

Specification of Letters Patent.

Patented April 17, 1906.

Original application fileclAugust 23, 1903, Serial No. 170,635. Divided and this application filed May 9, 1904. Serial No. 207,123.

To all whom, it may concern:

Be it known that 1, MARK TnoMAs DENNE, a subject of the King of Great Britain, residing at College street, Rushden, Northamptonshire, England, have invented new and useful Improvements in Thread-Measuring Mechanism for Boot and Shoe Sewing Machines, of which the following is a specification.

This invention relates to thread-measuring mechanism for boot and shoe sewing machines for welting and turn-shoe work, and more particularly of the kind in which a semirotary barbed needle, a semirotary awl or pricker, and a rotary shuttle moving in a plane at right angles to the needle and awl are employed, and comprises the improvements hereinafter described, and this application is a division of my former application, Serial No. 170,635, filed August 23, 1903, and which was patented September 26, 1905, under No.

In the accompanying drawings, Figure 1 is a sectional side elevation of a lock-stitch welting or turn-shoe sewing-machine provided with thread-measuring mechanism according to this invention. Fig. 2 is a side elevation of the said mechanism detached. Fig. 3 is a sectional plan of the thread-lock, the section being on the line 3 3, Fig. 2. Fig. 4 is a sectional plan of the pull-off, the section being on the line 4 4, Fig.2; and Fig. 5 is a section on the line 5 5, Fig. 2, but enlarged.

a is the frame of the machine, and Z) is the main or driving shaft. 6 is the semirotary curved needle, and (Z is the semirotary awl or pricker for feeding the work. e is the rotary shuttle for engaging the needle-thread and mounted in the shuttle-race g is the main take-up lever, h the auxiliary spring take-up, and 'L is the needle-thread tension-wheel. All the foregoing parts are of known construction.

The improvements are as follows:

A needlethread-lockin device is employed comprising two blocks j, Figs. 1, 2, and 3, having suitable gripping-surfaces between which the thread A passes from the tension-wheel Z to the pull-off device hereinafter described. The block is arranged to slide in a guide j Fig. 5, on the frame a and is actuated to grip the thread by the periphery of a disk Zc on the shaft 1) through the medium of a bell-crank lever 3' fulcrumed at 1' to the frame a, and a connecting rod or link 3' a cam-surface 3' being formed on the disk Zc on the shaft Z) to allow the grip on the thread to be relieved at the required time by the action of a spring 9' on the lever j. 1 The block j is carried by a pin 3' in a hole in the frame a, the part of the pin carrying the said block being formed eccentric to the main partof the pin, as shown clearly in Fig. 3, so that by rotating the said pin the block can be adjusted relatively with the block j.

v y' is a set-screw for locking the pin j when adjusted.

For pulling off the thread-ball the required amount of thread for the needle for each stitch a pull-off device is employed in the form of a bar or block Z, Figs. 1, 2, 4, and 5, carried upon a slide-block Z, working in a guide Z upon the frame a and reciprocated by a cam-groove Z in the disk 7c through the medium of a lever Z fulcrumed at Z to the frame a, and a connecting rod or link Z. The bar Z is adjustable upon the block Z, it being for this purpose provided with a slot Z through which pass set-screws Z into the said block. By adjusting the bar Z upon the block Z it will be seen that more or less thread can be pulled off at each backward move- -ment of the bar, according as it strikes the thread early or late during such movement.

The operation of the parts described is as follows: Assuming that a loop of the needlethread has been taken by the needle and drawn through the material to be sewed and that the shuttle has been passed through said loop at such period of the operation of the devices, the take-up lever 9 will be in its lowest position, with the blocks y' of the needlethread-locking device tightly grasping the needle-thread. The further movement of the machine will cause the take-up lever to draw the loop of needle-thread back through the material, bringing with it the shuttle thread and tightly interlocking the same in a well-known way. During this movement the auxiliary sprin take-up eases the positive draw of the ta e-up lever and prevents breakage in case of accidental detainment of the loop on the shuttle side of the material and also accommodates the mechanism in case the pull-off devices have failed to draw off the exact amount of thread required for the stitch. As soon as the take-up lever has reached its uppermost position the threadlocking device is released, the block moving forward to-do this. The pull-off device is then moved rearwardly, drawing off the allotted amount of thread for the next stitch. The

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thread-locking device then closes upon the thread and the pull-off resumes its normal position until the take-up lever has again reached its highest point.

Having noW particularly described and ascertained the nature of my said invention and in What manner the same is to be per formed, I declare that What I claim is 1. In a sewing-machine of the kind described, the combination With the take-up device, of a thread-locking device, said locking device comprising two blocks, means for moving one of said blocks and means including an eccentric for adjusting the other block, substantially as described.

2. In a sewing-machine of the kind hereinbefore described, the combination With a take-up mechanism including provision for elastically controlling the thread of a pull-off device comprising a sliding block, mechanism for reciprocating said block, a thread-engaging part having a slotted portion, and securing devices passing through said slotted portion and adjustably securing said thread-engaging part to said block, substantially as de scribed.

8. In a sewing-machine of the kind hereinbefore described, the combination With needle-thread tension device and take-up mechanism, of a pull-off device a thread-locking device adjacent to the pull-off device comprising, a stationary and a movable part, operating mechanism connected with said movable part, a rotatable supporting device for said stationary part having an eccentric portion engaging said stationary part Where by said stationary part may be adjusted by turning said rotatable supporting device, substantially as described.

MARK THOMAS DENNE.

Witnesses: Y H. RUssELL SMITI-Li FRANK WOODFORD. 

